Laurent Tranchant

Laurent Tranchant
SOLEIL synchrotron · Science Division

PhD

About

29
Publications
7,450
Reads
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223
Citations
Introduction
I work as a postdoctoral researcher on the PUMA beamline dealing with the analysis of ancient materials by X-ray fluorescence, X-ray absorption and X-ray diffraction. I am supporting users coming to the beamline in their experiments. My personal research project deals with the study of prehistoric mammoth ivories and bones to understand their diagenetic processes. Measurements are carried out at the PUMA beamline and at the NewAGLAE accelerator in the C2RMF.
Additional affiliations
September 2020 - present
SOLEIL synchrotron
Position
  • PostDoc Position
Description
  • I work as a postdoctoral researcher on the PUMA beamline dealing with the analysis of ancient materials by X-ray fluorescence, X-ray absorption and X-ray diffraction. I am supporting users coming to the beamline in their experiments. My personal research project deals with the study of prehistoric mammoth ivories and bones to understand their diagenetic processes. Measurements are carried out at the PUMA beamline and at the NewAGLAE accelerator in the C2RMF.
February 2015 - March 2018
Kyushu Institute of Technology
Position
  • Professor (Assistant)
Description
  • I worked as an assistant professor in the thermal device laboratory in Kyushu Institute of Technology. The purpose of my research project was to prove experimentally that surface electromagnetic waves could be efficient heat carriers in the case of suspended glass nanofilms. The increase of the thermal properties was successfully measured by means of the 3 omega and transient grating methods. I gave several radiative heat transfer seminars and managed six bachelor and master students.
November 2011 - January 2015
CentraleSupélec
Position
  • PhD Student
Description
  • During my PhD I proved theoretically and experimentally the existence of surface phonon-polaritons (SPhP) in glass microtubes. I developed an analytical model giving the characteristics of their propagation in different nanostructures and simulated their propagation by FDTD. I designed an experimental setup combining an IR microscope with a FTIR spectrometer to measure the thermal emission of a glass microtube. I taught the fabrication and the analysis of thin films to bachelor students.

Publications

Publications (29)
Article
As is well-known, the phonon and electron thermal conductivity of a thin film generally decreases as its thickness reduces to nanoscales due to size effects, which have dramatic engineering effects, such as the overheating, low reliability, and reduced lifetime of processors and other electronic components. However, given that thinner films have hi...
Article
Como es conocido, la conductividad térmica de una película delgada generalmente disminuye a medida que su espesor se reduce a través de valores nanométricos (Liu & M. Asheghi, 2006); esto genera el sobrecalentamiento y la reducción de la vida útil de procesadores y otros componentes electrónicos (Pop, 2010). Sin embargo, dado que las películas más...
Article
Based on the ability of plane structures to simultaneously optimize the propagation, confinement, and energy of surface plasmon-polaritons or surface phonon-polaritons, we develop the polaritonic figure of merit Z = βR*Λ^2 /δ, where βR , Λ and δ are the longitudinal wave vector, propagation length, and penetration depth, respectively. Explicit and...
Article
We fabricated a stacked type thermoelectric module ( 4mm × 4mm ) on a 4pm SiNx free-standing film using a vacuum deposition process through a shadow mask. We proposed the structure of the device to the multi-layered structure to decrease the electrical resistance of the device. Cu and Ni were used as thermoelectric materials. A silver paste was pain...
Article
The Sliver-Alumina-cermet was fabricated by using metal organic decomposition method (MOD) in large area by low costs. The metal organic solvent with silver nano-particles was spin coated on the glass film with a deposited silver thin film, and heated up at 100ºC by a hot plate. The spectral normal-hemispherical reflectance of the samples with diff...
Article
We demonstrate that the energy transport of surface phonon polaritons can efficiently be observed in a crystal made up of a three-dimensional assembly of spheroidal nanoparticles of silicon carbide. The ultralow phonon thermal conductivity of this nanostructure, along with its high surface area-to-volume ratio, allows the predominance of the polari...
Article
Full-text available
In this study, we fabricated micro thermoelectric power generator using freestanding film substrate, and we evaluated the performance of the generator from the standpoint of thermoelectric performance and thermal design. We fabricated a SiNx free-standing film substrate about 5 μm thick on Si wafer, using MEMS processes. Then, we prepared for both...
Article
We investigated the spectral emittance of a gold-coated micro-particle array. We measured the spectral normal emittance of the samples. The diameter of micro-particles is 5 mm. We changed the number of layers of micro-particles. From the measurement result, enhancement of emittance has been checked at the wavelength of 5 mm. This enhancement of emi...
Article
We analyze in detail the energy transport of surface phonon polaritons propagating in a chain of spheroidal polar nanoparticles with both longitudinal and transversal polarizations. Explicit and closed-form expressions for the dispersion relation and propagation length are derived and used to determine the values of the nanoparticle polarizability...
Article
Focusing of surface phonon-polaritons propagating toward the tip of a cone and the edge of a wedge is theoretically analyzed and compared. Based on Maxwell's equations, explicit expressions for the dispersion relations in each structure are determined and solved numerically for a propagation parameter driving the surface phonon-polariton energy den...
Article
Full-text available
Miniaturization of transistors, whose sizes reach a few tens of nanometers nowadays,implies new problems of heat control at very short scales. This big challenge among others enabled the emergence of nanoscale heat transfer as a new research domain. Near-field heat transfer is one of the axis of this thematic.It concerns the behavior of thermal wav...
Conference Paper
Full-text available
Modern microelectronics technology requires developing more efficient ways of heat extraction and device cooling at the tens-nanometer scale. The thermal conductivity of materials decreases as their characteristic sizes are scaled down, while the influence of the surface effects increases with the growth of surface-to-volume fraction. This is why t...
Article
The reflection and transmission coefficients of a surface phonon-polariton propagating along the surface of a thin film of SiO 2 and crossing the interface of two dielectric media are analytically determined. Based on the expansion of the electrical and magnetic fields in terms of normal modes, explicit expressions for the reflectivity and transmis...
Conference Paper
Thermal conductivity of nanofilms of SiO2 and SiC due to the propagation of surface phonon-polaritons is comparatively studied. We analytically demonstrate that the thermal conductivity of suspended nanofilms is a linear combination of the inverse first and third powers of the film thickness. It is shown that: i) A 50 nm-thick film of SiC at 500 K...
Article
Based on the Landauer formalism, we demonstrate that the thermal conductance due to the propagation of surface phonon-polaritons along a polar nanowire is independent of the material characteristics and is given by Pi^2kB^2T/3h. The giant propagation length of these energy carriers establishes that this quantization holds not only for a temperature...
Article
The effective thermal conductivity of a layered system due to the propagation of surface phonon-polaritons is studied. We analytically demonstrate that the thermal conductivity of a set of nanolayers can be described as one of a single layer with an effective permittivity, which does not ordinarily appear in nature and depends on the permittivities...
Article
The effects of the permittivity anisotropy and size of a nano thin film on its thermal conductivity due to surface phonon-polaritons are studied. We demonstrate that this thermal conductivity is a linear combination of the inverse first and third powers of the film thickness. For a 100-nm-thick film of α-quartz surrounded by air, the thermal conduc...
Conference Paper
Full-text available
Surface phonon-polaritons (SPP) are hybrid electromagnetic waves that are the result of the coupling between photons and phonons at the interface between two different media [1,2]. Taking into account that the surface effects predominate over the volumetric ones due to the high surface area/volume ratio in nanomaterials, the energy transport by SPP...
Article
Full-text available
The surface phonon-polaritons contribution to the thermal conductivity of a nano thin film of silicon dioxide is investigated based on the Maxwell equations and the Boltzmann transport equation. It is shown that: (1) a small difference between the permittivities of the substrate and superstrate of the film can generate giant propagation lengths and...
Article
Full-text available
We report a temperature measurement of the surface of micro structured glass tube, affected by surface phonon polaritons' (SPPs) energy enhancement. The glass tubes were designed to guide monochromatic thermal energy to improve heat conduction or serve as radiative source. The simulation results show strong enhancement of the Free Path when a wave...
Article
Full-text available
Calculations of the dispersion relation and of the propagation length of surface phonon-polariton modes in a micrometric glass waveguide have been performed. The dispersion relation was solved in two ranges of frequency where SPP appear in glass. We succeeded in showing a maximal propagation length of 35 µm in a 10 µm radius waveguide with a 1 µm t...
Article
Full-text available
We report the characterization of correlated photon pairs generated in dispersion-engineered silicon slow-light photonic crystal waveguides pumped by picosecond pulses. We found that taking advantage of the 15-nm flat-band slow-light window (vg ~ c/30), the bandwidth for correlated photon-pair generation in 96- and 196-μm-long waveguides was at lea...

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